Agglomerative Magnets and Informal Regulatory Networks: Electricity Market Design Convergence in the USA and Continental Europe

The absence of one broadly accepted design template for liberalised electricity markets induces regulatory competition and institutional diversity. Focussing on continental Europe and the USA, this analysis explores how agents and structures accelerate or impede the move to one standard market design in the electricity sector. It reveals that market design convergence in Europe is driven by the 'Florence Consensus,' a tripartite coalition between the European Commission fostering European integration and the internal market, informal regulatory networks between grid operators, standardisation authorities and regulators, who have been coordinating their actions in the 'Florence Forum,' and epistemic communities exemplified in the Florence School of Regulation. In contrast, the United States' Federal Energy Regulatory Commission lacks support among politicians, many states' public utility commissions, the neo-liberal intelligentsia and even industrial lobbying groups to effectively push for a standardised market design. However, design convergence in the USA may be induced by the gradual expansion of multi-state markets operated by regional transmission organisations.Electricity, Deregulation, Regulatory Competition, Policy Diffusion

Lifetime of the surface magnetoplasmons in metallic nanoparticles

We study the influence of an external magnetic field on the collective electronic excitations in metallic nanoparticles. While the usual surface plasmon corresponding to the collective oscillation of the electrons with respect to the ionic background persists in the direction parallel to the magnetic field, the components in the perpendicular plane are affected by the field and give rise to two collective modes with field-dependent frequencies, the surface magnetoplasmons. We analyze the decay of these collective excitations by their coupling to particle-hole excitations and determine how their lifetimes are modified by the magnetic field. In particular, we show that the lifetime of the usual surface plasmon is not modified by the magnetic field, while the lifetime of the two surface magnetoplasmons present a weak magnetic-field dependence. Optical spectroscopy experiments are suggested in which signatures of the surface magnetoplasmons may be observed.Comment: 11 pages, 6 figures; published versio

Inpainting of Cyclic Data using First and Second Order Differences

Cyclic data arise in various image and signal processing applications such as interferometric synthetic aperture radar, electroencephalogram data analysis, and color image restoration in HSV or LCh spaces. In this paper we introduce a variational inpainting model for cyclic data which utilizes our definition of absolute cyclic second order differences. Based on analytical expressions for the proximal mappings of these differences we propose a cyclic proximal point algorithm (CPPA) for minimizing the corresponding functional. We choose appropriate cycles to implement this algorithm in an efficient way. We further introduce a simple strategy to initialize the unknown inpainting region. Numerical results both for synthetic and real-world data demonstrate the performance of our algorithm.Comment: accepted Converence Paper at EMMCVPR'1

A Second Order TV-type Approach for Inpainting and Denoising Higher Dimensional Combined Cyclic and Vector Space Data

In this paper we consider denoising and inpainting problems for higher dimensional combined cyclic and linear space valued data. These kind of data appear when dealing with nonlinear color spaces such as HSV, and they can be obtained by changing the space domain of, e.g., an optical flow field to polar coordinates. For such nonlinear data spaces, we develop algorithms for the solution of the corresponding second order total variation (TV) type problems for denoising, inpainting as well as the combination of both. We provide a convergence analysis and we apply the algorithms to concrete problems.Comment: revised submitted versio

Two interacting particles in a disordered chain IV: Scaling of level curvatures

The curvatures of two-particle energy levels with respect to the enclosed magnetic flux in mesoscopic disordered rings are investigated numerically. We find that the typical value of the curvatures is increased by interactions in the localised regime and decreased in the metallic regime. This confirms a prediction by Akkermans and Pichard (Eur. Phys. J. B 1, 223 (1998)). The interaction-induced changes of the typical curvatures at different energies and disorder strengths exhibit one-parameter scaling with a conductance-like single parameter. This suggests that interactions could influence the conductance of mesoscopic systems similarly.Comment: 9 pages, 7 figures. Other parts of the series: cond-mat/9706258, cond-mat/9801134, cond-mat/980813

Delocalization due to correlations in two-dimensional disordered systems

We study the spectral statistics of interacting spinless fermions in a two-dimensional disordered lattice. Within a full quantum treatment for small few-particle-systems, we compute the low-energy many-body states numerically. While at weak disorder the interactions reduce spectral correlations and lead to localization, for the case of strong disorder we find that a moderate Coulomb interaction has a delocalizing effect. In addition, we observe a non-universal structure in the level-spacing distribution which we attribute to a mechanism reinforcing spectral correlations taking place in small systems at strong disorder.Comment: 6 pages, 4 figures, corrected typo

Persistent currents for Coulomb interacting electrons on 2d disordered lattices: Sign and interaction dependence in the Wigner crystal regime

A Wigner crystal structure of the electronic ground state is induced by strong Coulomb interactions at low temperature in clean or disordered two-dimensional (2d) samples. For fermions on a mesoscopic disordered 2d lattice, being closed to a torus, we study the persistent current in the regime of strong interaction at zero temperature. We perform a perturbation expansion starting from the Wigner crystal limit which yields power laws for the dependence of the persistent current on the interaction strength. The sign of the persistent current in the strong interaction limit is independent of the disorder realization and strength. It depends only on the electro-statically determined configuration of the particles in the Wigner crystal.Comment: 13 pages, 4 figures, final version (introduction and discussion extended